As an example, we will use the following problem:

Maximize	x1 + 2x2 + 3x3
subject to	-x1 + x2 + x3 20 x1 - 3x2 + x3 30
with these bounds	0 x1 40 0 x2 + 0 x3 +

This problem has three variables (x1, x2, and x3) and two less-than-or-equal-to constraints.

The enter command is used to enter a new problem from the keyboard. The procedure is almost as simple as typing the problem on a page. At the CPLEX> prompt type:

enter

A prompt appears on the screen asking you to give a name to the problem that you are about to enter.

The problem name may be anything that is allowed as a file name in your operating system. If you decide that you do not want to enter a new problem, just press the <return> key without typing anything. The CPLEX> prompt will reappear without causing any action. The same can be done at any CPLEX> prompt. If you do not want to complete the command, simply press the <return> key. For now, type in the name example at the prompt.

Enter name for problem: example

The following message appears:

Enter new problem ['end' on a separate line terminates]:

and the cursor is positioned on a blank line below it where you can enter the new problem.

You can also type the problem name directly after the enter command and avoid the intermediate prompt.

The syntax for entering a problem is:

enter problem name